Answer:
2.25g of NaF are needed to prepare the buffer of pH = 3.2
Explanation:
The mixture of a weak acid (HF) with its conjugate base (NaF), produce a buffer. To find the pH of a buffer we must use H-H equation:
pH = pKa + log [A-] / [HA]
<em>Where pH is the pH of the buffer that you want = 3.2, pKa is the pKa of HF = 3.17, and [] could be taken as the moles of A-, the conjugate base (NaF) and the weak acid, HA, (HF). </em>
The moles of HF are:
500mL = 0.500L * (0.100mol/L) = 0.0500 moles HF
Replacing:
3.2 = 3.17 + log [A-] / [0.0500moles]
0.03 = log [A-] / [0.0500moles]
1.017152 = [A-] / [0.0500moles]
[A-] = 0.0500mol * 1.017152
[A-] = 0.0536 moles NaF
The mass could be obtained using the molar mass of NaF (41.99g/mol):
0.0536 moles NaF * (41.99g/mol) =
<h3>2.25g of NaF are needed to prepare the buffer of pH = 3.2</h3>
False, gravity is a force, matter has mass and volume.
Answer:
What r u trying to ask? you need to put more stuff in your question on here so we can answer it.
Explanation:
Answer:
1= K⁺= (Z=19) = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s⁰
2 = Zn²⁺= (Z = 30) =1s² 2s² 2p⁶ 3s² 3p⁶ 4s⁰, 3d¹⁰
Explanation:
When an atom lose or gain the electron ions are formed. There are two types of ions cation and anion.
Cation are formed when atom lose the electron.
Anion are formed when an atom gain the electron.
In given question potassium loses its valance electron and form K⁺ cation. Thus its electronic configuration will be written as,
₁₉K⁺ = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s⁰
While the electronic configuration of potassium in neutral form is:
₁₉K = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
The atomic number of zinc is 30 and its electronic configuration is:
₃₀Zn= 1s² 2s² 2p⁶ 3s² 3p⁶ 4s², 3d¹⁰
When zinc atom loses its 2 valance electrons the electron configuration will be,
₃₀Zn²⁺= 1s² 2s² 2p⁶ 3s² 3p⁶ 4s⁰, 3d¹⁰